<style>
.aa-select {
    position: relative;
}

.aa-down {
    position: absolute;
    top: 0;
    right: 0;
    width: 20px;
    height: 100%;
    text-align: center;
}

.arrow {
    border-left: 4px solid #fff;
    border-right: 4px solid #fff;
    border-top: 4px solid #000000;
    font-size: 0;
}
.aa-drop-select {
    background-color: #FFFFFF;
    border: 1px solid #000;
    border-radius: 0 0 0 0;
    float: left;
    list-style: none outside none;
    margin: 0;
    padding: 0;
    position: absolute;
    z-index: 1000;
    max-height: 200px;
    overflow-y: auto;
}

.aa-drop-select li:hover {
    background-color: #00f;
    color: #fff;
}

.show-more {
    cursor: pointer;
    font-size: .9em !important;
    color: #999 !important;
    
}
.show-more:hover {
    background-color: #fff !important;
    color: #33f !important;
}
</style>
<div class="form-inline">
  <input type="button" class="btn" id='load' value="Load" />
  <div class="form-group aa-select">
    <label class="sr-only" for="radio_conf">Select</label>
    <input type="email" class="form-control" id="radio_conf" placeholder="Select">
    <a class="aa-down" href="javascript:;"><span class="arrow"></span></a>
  </div>
</div>
